Lid opening/closing system for closed container, contained object insertion/takeout system having same lid opening/closing system, and substrate processing method using same lid opening/closing system

ABSTRACT

A tunnel is provided between a portion on a support mechanism on which a pod is loaded and a mini environment that is in communication with a FIMS. The pod is located in the tunnel when a lid of the pod is detached from the pod after the lid is held by a door. The pod is also located in the tunnel when it is at a position that allows transfer of wafers and to which the pod is moved after detachment of the lid. The lid and the door that have been separated from the pod can also be housed in a housing space annexed to the tunnel. A light emitting portion and a light receiving portion of an optical sensor are provided respectively on opposed walls of the tunnel. A pod is provided with a detection window that can transmit detection light.

This application claims priority from Japanese Patent Application No. 2008-137932 filed on May 27, 2008, which is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a type of a so-called FIMS (Front-Opening Interface Mechanical Standard) system that is used when reticles, wafers or the like stored in the interior of a transfer container called a pod are transferred from one semiconductor processing apparatus to another in a semiconductor manufacturing process etc. More specifically, the present invention relates to a FIMS system or a lid opening and closing system that can handle, at the same time, a plurality of pods each storing a few reticles or the like therein and open/close the lids of the pods to bring reticles or the like into/out of the pods. Here, the pod is what is called a FOUP (Front-Opening Unified Pod) or a low profile closed container. The present invention also relates to a substrate processing method using such a system.

2. Description of the Related Art

Previously, the semiconductor manufacturing process had been performed in what is called a clean room that is constructed by establishing a high degree of cleanliness in the room in which semiconductor wafers are handled. In recent years, however, in view of an increase in the wafer size and with a view to reduce cost incurred in maintenance of the clean room, use has been made of a method of keeping clean only the interior of a processing apparatus, a pod (or wafer container) and a mini-environment through which substrates or wafers are transferred between the pod and the processing apparatus.

The pod is composed of a substantially cubical body portion having shelves provided therein that can hold a plurality of wafers in a parallel and separated state and an opening provided on one side thereof through which wafers can be brought into/out of it, and a lid for closing the opening. Those pods which have an opening portion provided not on the bottom but on one lateral side thereof (i.e. the side to be directly opposed to the mini-environment) are collectively called FOUPs (Front-Opening Unified Pods). The present invention is directed mainly to technologies in which the FOUP is used. Previously, pods that can each house ten or more wafers had been used to increase the production efficiency. Recently, however, with an increase in the diameter of wafers or an increase in the number of steps of wafer processing, it has been considered preferable that only a few wafers be stored in one pod and wafers be supplied to each apparatus in a small lot. A low profile pod that is specialized to house such a few wafers and handling of such pods are described in detail in Japanese Patent Application Laid-Open No. 2004-262654.

A system that constitutes the above mentioned mini environment has a first opening portion opposed to the opening of the pod, a door that closes the first opening portion, a second opening portion or processing apparatus side opening portion provided on the semiconductor processing apparatus side, and a transferring robot that is adapted to reach into the interior of the pod through the first opening portion to pick up a wafer and transfer the wafer into the processing apparatus through the second opening portion on the processing apparatus side. The system that constitutes the mini environment also has a support table that supports the pod in such a way that the pod opening is placed just in front of the door. Typically, the support table is adapted to be movable toward and away from the door over a predetermined distance. When the wafers in the pod are to be transferred into the processing apparatus, the pod placed on the support table is moved until the lid of the pod abuts the door, and then after abutment, the lid is detached by the door, whereby the opening of the pod is opened. By this process, the interior of the pod and the interior of the processing apparatus are bought into communication with each other through the mini environment to allow wafer transferring operations that will be performed repeatedly. All of the support table, the door, the pod side first opening portion, a mechanism for opening/closing the door and walls partly defining the mini environment and having the first opening portion are included in what is referred to as a lid opening and closing system or an FIMS (Front-opening Interface Mechanical Standard) system in the context of the present invention.

As described above, in the past, systems that handle only one pod in which ten or more wafers are stored have mainly been used. However, in the case where the above mentioned low profile pods are used, it is demanded, in order to reduce the process time, that a plurality of pods can be operated at the same time or the time period over which a pod is on the table can overlap the time period over which another pod is on the table when wafers are supplied into the mini environment. This wafer handling operation can also be applied to transfer of other objects such as reticles that are used in exposure process. In the case where a plurality of low profile pods are to be handled, the plurality of pods may be arranged one above another along a vertical direction to make the area occupied by the system small. A lid opening and closing system in which pods are arranged in this way has been developed and disclosed in Japanese Patent Application Laid-Open No. 2000-286319. In this system, a plurality of pod side opening portions like that described above are arranged along the vertical directions, and each door that closes each opening portion is adapted to be swung about a shaft extending in the longitudinal direction of the opening portion having a rectangular shape, whereby the space occupied by the mechanism for opening and closing the doors is made small.

A conventional pod that stores a number of wafers at the same time is transported between processing apparatuses so that the all the wafers stored in the pod are subjected to a certain processing in each processing apparatus. In some cases, however, there may be a wafer(s) that does not satisfy a predetermined standard after processing, and such a wafer(s) is removed from the pod. Therefore, although all the shelves in the pod held wafers at the time when the process was started, some of the shelves become empty by removal of wafers as the process proceeds. Each of the processing apparatuses is substantially automated. If there is a lack of wafer(s) as described above, it is necessary to detect the lack or absence of wafer(s) and perform appropriate transfer of wafers out of/into the pod taking into account the absence of wafer(s). Therefore, in the case where a conventional pod that stores a number of wafers at the same time is used, it is necessary to perform what is called a mapping operation, or the operating of detecting in which storage shelves in the pod wafers are stored, in each of the processing apparatuses (see Japanese Patent Application Laid-Open No. 2004-153281).

In the case where the pod for storing a smaller number of wafers according to the present invention is used, it is also necessary to perform the mapping operation as with the above described conventional pod. In a conventional mapping operation described in the Japanese Patent Application Laid-Open No. 2004-153281, the presence/absence of wafers is detected by inserting a so-called mapping sensor having a light emitting portion and a light receiving portion that are paired into the interior of the pod and moving the sensor along the direction of arrangement of the wafers in a scanning manner. If, for example, the mapping sensor etc. disclosed in the Japanese Patent Application Laid-Open No. 2004-153281 is to be applied to the apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-286319, it is necessary that the mapping sensor and means for carrying the mapping sensor into the interior of the pod and moving it in a specific direction be provided in the mini environment. However, in the case of the apparatus in which multiple pods are arranged one above another as is the case with the apparatus shown in Japanese Patent Application Laid-Open NO. 2000-286319, it is difficult to provide a space for accommodating the mapping sensor itself. Even if there is a space for the mapping sensor, it should not be allowed to provide a plural number of such structures in the mini environment, from which, by its nature, driving structure should be eliminated as much as possible, since the mini environment is to be kept clean. Therefore, there is a demand for a mapping sensor has a structure different from that described above and can suitably be used with a pod and load port for handling a small number of wafers.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above-described problem, and has as an object to provide a lid opening and closing system for a closed container or pod for storing a small number of wafers that can map the wafers contained in the pod. It is also an object of the present invention to provide a substrate processing method using such a system.

To achieve the above described object, according to the present invention, there is provided a lid opening and closing system that detaches a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored (contained object) in the interior thereof and the lid that can be detached from the main body and close the opening to form a closed space in cooperation with the main body, to open the opening thereby enabling transfer of the object to be stored into/out of the storage container, comprising: a storage container support mechanism that supports the storage container and can move the storage container along a predetermined direction; a mini environment separated from an exterior space, in which a mechanism that transfers the object to be stored is housed under dust control; a tunnel having an exterior space side opening portion disposed near a position at which the storage container support mechanism is loaded with the storage container and a mini environment side opening portion that opens to the mini environment to establish communication with the mini environment; a door that can open and close the mini environment side opening, the door having a holding mechanism that is in contact with and holds the lid and being movable, in a posture in which it is oriented perpendicular to the direction in which the tunnel extends to substantially close the tunnel, along the predetermined direction relative to the storage container that is moved by the storage container support mechanism disposed in the tunnel; and a mapping sensor provided within the tunnel, that includes a light emitting portion that emits detection light to an object to be stored held in the storage container and a light receiving portion that receives the detection light, to detect the presence/absence of the object to be stored.

In the above described lid opening and closing system, it is preferred that the light emitting portion and light receiving portion be disposed in accordance with the position of the object to be stored in the interior of the storage container in a state in which the storage container is located at a position at which transfer of the object to be stored into/out of the storage container is performed. It is also preferred that there be a plurality of objects to be stored like the aforementioned object to be stored, a plurality of mapping sensors like the aforementioned mapping sensor be provided for the object to be stored respectively, and at least one of a wavelength range and an emission frequency of the detection light used by the mapping sensors differ among the mapping sensors. In the case where there are a plurality of objects to be stored, it is preferred that a plurality of mapping sensors like the aforementioned mapping sensor be provided for the respective objects to be stored, and the light emitting portion of one of the mapping sensors and the light receiving portion of the mapping sensor disposed just above or below the one mapping sensor be disposed on an inner surface of the tunnel and at a position opposed to one side of the storage container. In the case where there are plurality of objects to be stored, it is preferred that a plurality of mapping sensors be provided for the respective objects to be stored, the light emitting portion of a first mapping sensor among the plurality of mapping sensors and the light emitting portion of a second mapping sensor among the plurality of mapping sensors that is disposed just above or below the first mapping sensor be disposed on an inner surface of the tunnel and at positions opposed to one side of the storage container, and the distance between an axis of detection light emitted from the light emitting portion of the first mapping sensor and an axis of detection light emitted from the light emitting portion of the second mapping sensor increase away from the light emitting portions. It is also preferred that a light emission side end of the light emitting portion and a light receiving side end of the light receiving portion be disposed in such a way as to be flush with or recessed from the inner surface of the tunnel.

To achieve the above object, according to the present invention, there is provided a lid opening and closing system that detaches a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored in the interior thereof and the lid that can be detached from the main body and close the opening to form a closed space in cooperation with the main body, to open the opening thereby enabling transfer of the object to be stored into/out of the storage container, comprising: a storage container support mechanism that supports the storage container and can move the storage container along a predetermined direction; a mini environment separated from an exterior space, in which a mechanism that transfers the object to be stored is housed under dust control; a tunnel having an exterior space side opening portion disposed near a position at which the storage container support mechanism is loaded with the storage container and a mini environment side opening portion that opens to the mini environment to establish communication with the mini environment; and a door that has a holding mechanism that is in contact with and holds the lid, is disposed inside the tunnel, can swing about a rotational axis perpendicular to the predetermined direction and parallel to a plane in which the object to be stored extends, and is movable, in a posture in which it is oriented perpendicular to the direction in which the tunnel extends to substantially close the tunnel, along the predetermined direction relative to the storage container that is moved by the storage container support mechanism disposed in the tunnel, wherein the tunnel allows the opening of the storage container to be located in the tunnel when the door has moved relative to the storage container to detach the lid from the storage container and has a size large enough to have a housing space that can house the door and the lid without interfering with movement of the storage container in the predetermined direction when the door with the lid held by it has been swung about the rotational axis, and a mapping sensor that includes a light emitting portion that emits detection light to an object to be stored held in the storage container and a light receiving portion that receives the detection light, to detect the presence/absence of the object to be stored, is provided within the tunnel.

In the above described lid opening and closing system, it is preferred that the light emitting portion and light receiving portion be disposed in accordance with the position of the object to be stored in the interior of the storage container in a state in which the storage container is located at a position at which transfer of the object to be stored into/out of the storage container is performed. It is also preferred that there be a plurality of objects to be stored like the aforementioned object to be stored, a plurality of mapping sensors like the aforementioned mapping sensor be provided for the object to be stored respectively, and at least one of a wavelength range and an emission frequency of the detection light used by the mapping sensors differ among the mapping sensors.

To achieve the above object, according to the present invention, there is provided an object to be stored transfer system that transfers an object to be stored into/out of a storage container using a lid opening and closing system, comprising any one of the above described lid opening and closing system and a storage container, wherein the storage container is provided with a first detection window that can transmit the detection light and allows the detection light emitted from the light emitting portion to reach the corresponding object to be stored and a second detection window that can transmit the detection light and allows the detection light to reach the light receiving portion from the interior of the storage container. In this system, in the case where there are a plurality of objects to be stored like the aforementioned object to be stored, it is preferred that the first detection window and the second detection window be provided separately for the respective corresponding objects to be stored.

To achieve the above object, according to the present invention, there is provided an object to be stored processing method for detaching a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored in the interior thereof and the lid that can be detached from the main body and close the opening to form a closed space in cooperation with the main body to open the opening thereby enabling transfer of the object to be stored into/out of the storage container, transferring the object to be stored into/out of the storage container, and performing a predetermined processing on the object to be stored in the exterior of the storage container, comprising the steps of: preparing a lid opening and closing system including a dust-controlled mini environment, an object transfer mechanism which transfers an object and is provided in the mini environment, a door that can substantially close an opening portion of the mini environment and hold the lid, and a support mechanism that supports the storage container and moves the storage container in a predetermined direction to cause the door to hold the lid; causing the storage container to be supported on the support mechanism and fixing the storage container on the support mechanism; driving the support mechanism to cause the lid to abut to the door thereby causing the door to hold the lid; driving the support mechanism and the door in the predetermined direction relative to each other to thereby separate the storage container and the lid; swinging the lid and door about an axis that is perpendicular to the predetermined direction and contained in a plane in which the object to be stored extends to thereby bring the lid and door out of a moving region of the storage container; and driving the storage container in the predetermined direction to set it at a position at which transfer of the object to be stored into/out of the storage container is performed, wherein the storage container is located inside a tunnel that connects the mini environment and a space in which operation of causing the storage container to be supported on the support mechanism is performed at the time when the lid is separated from the storage container, the lid and door are located inside the tunnel after the swinging, and the storage container is located inside the tunnel when it is located at the position at which transfer of the object to be stored into/out of it is performed, when the storage container is located at the position at which transfer of the object to be stored is performed, detection light is cast to the object to be stored through a first detection window that can transmit the detection light provided on the storage container, and whether the object to be stored is present or absent is determined based on whether or not the detection light reflected by the object to be stored is received through a second detection window that can transmit the detection light.

According to the present invention, it is possible to detect whether wafers are stored in a pod for storing a small number of wafers at any time during the lid opening or closing operation. According to the present invention, sensors may be provided for respective wafers, and detection errors attributed to interference between sensors can be prevented. Thus, a reliable detection result can be obtained. According to the present invention, the sensor is fitted in a recess provided in the interior of the tunnel in which ceaseless air flow directed from the mini environment side to the exterior space side is created. Thus, the presence of the sensor does not lead to a decrease in the degree of cleanness in the mini environment.

The above and other objects, features, and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view schematically shows the general structure of the relevant portion of a lid opening and closing system according to an embodiment of the present invention and a pod set on that system.

FIG. 1B is a schematic cross sectional view taken along line 1B-1B in FIG. 1A.

FIG. 1C schematically shows the structure shown in FIG. 1A as seen from the direction indicated by arrow 1C in FIG. 1A.

FIG. 1D schematically shows the structure shown in FIG. 1A as seen from the direction indicated by arrow 1D in FIG. 1A.

FIG. 2 illustrates, in a manner similar to FIG. 1A, the structure shown in FIG. 1A in the state in which a lid 4 is in contact with and held by a door 15 after the pod 2 has been moved.

FIG. 3A illustrates, in a manner similar to FIG. 1A, the structure shown in FIG. 1A in the state in which the pod 2 has been once moved backward and the lid 4 has been detached from the pod main body 2 a.

FIG. 3B is a schematic cross sectional view taken along line 3B-3B in FIG. 3A.

FIG. 4A illustrates, in a manner similar to FIG. 1A, the structure shown in FIG. 1A in the state in which the lid 4 and the door 15 has been received in the housing space 20 c after the door 15 has been swung.

FIG. 4B is a schematic cross sectional view taken along line 4B-4B in FIG. 4A.

FIG. 5A illustrates, in a manner similar to FIG. 1A, the structure shown in FIG. 1A in the state in which the pod 2 has been moved to a wafer transfer position at which the operation of transferring a wafer 1 into/out of the pod 2 can be performed.

FIG. 5B is a schematic cross sectional view taken along line 5B-5B in FIG. 5A.

FIG. 5C schematically shows the structure shown in FIG. 5A as seen from the direction indicated by arrow 5C in FIG. 5A, where illustrations of the lid and the pod main body are omitted.

FIG. 6 shows the definition of various dimensions in an embodiment of the present invention.

FIG. 7A shows, in a manner similar to FIG. 5, an embodiment of the present invention in which the structure like that shown in FIG. 1A is equipped with sensors for wafer mapping. FIG. 7A shows the state in which the pod 2 has been moved to a wafer transfer position at which the operation of transferring a wafer 1 into/out of the pod 2 can be performed.

FIG. 7B is a schematic cross sectional view taken along line 7B-7B in FIG. 7A.

FIG. 7C schematically shows the structure shown in FIG. 7A as seen from the direction indicated by arrow 7C in FIG. 7A, where illustrations of the lid and the pod main body are omitted.

FIG. 8 illustrates, in a manner similar to FIG. 7C, another embodiment of the present invention.

FIG. 9 illustrates, in a manner similar to FIG. 7C, still another embodiment of the present invention.

FIG. 10 illustrates, in a manner similar to FIG. 7C, yet another embodiment of the present invention.

FIG. 11 schematically illustrates the general structure of a substrate processing apparatus according to an embodiment of the present invention.

FIG. 12 is an enraged view of the relevant portion of the apparatus according to the present invention shown in FIG. 11.

FIG. 13 illustrates, in a manner similar to FIG. 12, another embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

In the following embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the present invention, the relevant structures other than the sensor will be described first to facilitate description of the embodiment of the present invention. FIG. 1A schematically illustrates a part of a low profile pod and the relevant portion of a lid opening and a closing system that can handle an individual pod independently, as seen from the side. In practice, a plurality of structures or systems like that shown in FIG. 1A are arranged one above another along the vertical direction. To facilitate explanation, the following description of the embodiment will be directed to one system. FIG. 1B is a cross sectional view taken along line 1B-1B in FIG. 1A, showing the structure shown in FIG. 1A. FIG. 1C illustrates the structure shown in FIG. 1A as seen from the direction indicated by arrow 1C in FIG. 1A (i.e. as seen from the mini environment). FIG. 1D illustrates the structure shown in FIG. 1A except for the pod as seen from the direction indicated by arrow 1D in FIG. 1A (i.e. as seen from the exterior space).

FIG. 1A illustrates a state in which the pod is set on a predetermined position on the support table that will be described later. FIG. 2A illustrates a state in which the lid of the pod is held by a door after the pod has been once driven to advance. FIG. 3A illustrates a state in which the lid has been removed from the pod after the pod has been once driven to retract. FIG. 4A illustrates a state in which the lid opening and closing mechanism and the lid have been moved by an operation of the lid opening and closing mechanism to a housing space for them in the interior of a tunnel. FIG. 5A illustrates a state in which the pod is at a predetermined position that allows wafer transfer from/into it after the pod has been driven to advance further. FIGS. 3B, 4B, and 5B illustrate the states shown in FIGS. 3A, 4A and 5A respectively, in the same manner as FIG. 1B. FIG. 5C illustrates the state shown in FIG. 5A in the same manner as FIG. 1C. Note that the pod and the lid are not illustrated in FIG. 5C to facilitate understanding.

First, a description will be made of a pod to be set on this lid opening and closing mechanism and wafers stored in the pod. In the interior of the body 2 a of the pod 2 is a space in which two wafers or objects to be processed are to be housed or stored. The pod main body 2 a is of a low-profile box-like shape and has an opening 2 b on one of the lateral sides thereof. The pod 2 also has a lid 4 that closes the opening 2 b of the body 2 a. In the interior of the body 2 a is provided a rack (not shown) having a plurality of shelves (two shelves, in this embodiment, which are not shown in the drawings) on which wafers 1 are held horizontally one above another along the vertically direction. The wafers 1 placed on the shelves are disposed at a constant interval in the interior of the pod 2. The wafer 1 is an example of the object to be stored according to the present invention. The pod 2 is an example of the storage container according to the present invention. The body 2 a, which has a basically box-like shape, is an example of the body that is defined to have a substantially box-like shape according to the present invention. The opening 2 b of the pod 2, which has a basically rectangular shape, is an example of the opening having a substantially rectangular shape according to the present invention.

The lid opening and closing system 10 according to the present invention includes a support table 13, a door 15, a tunnel member 21 that defines a tunnel 20, a door opening and closing mechanism 30 and a wall 11 which is a member that partly constitutes the outer wall of a mini environment 25 (or a transfer chamber that will be described later) with which the tunnel is in communication. The support table 13 has a movable plate 14 having a flat surface on the top thereof on which the pod 2 is actually to be placed. The movable plate 14 can move the pod placed thereon toward and away from a first opening portion 10. Positioning pins 14 a are implanted on the flat surface of the movable plate 14. The positioning pins 14 a are adapted to be fit into positioning recesses (not shown) provided on the bottom surface of the pod main body 2 a to uniquely determine the positional relationship between the pod 2 and the movable plate 14. The movable plate 14 a is connected with a known drive mechanism (not shown) including a stepping motor, a ball screw and other parts, and the movable plate 14 a on which the pod 2 is set can be stopped at four positions that will be described later. The four positions include the pod 2 load position, the lid holding position, the lid detaching position and the wafer transfer position. The structure including the support table 13 and the movable plate 14 functions as the storage container support mechanism or the support mechanism that supports the pod and moves it in a predetermined direction according to the present invention.

The tunnel member 21 includes a peripheral wall portion 21 a that extends from the wall 11 perpendicularly thereto or in the direction parallel to the moving direction of the movable plate 14 toward the exterior space and has a rectangular cross section that is perpendicular to the direction it extends and an end wall portion 21 b that partly limits the opening of the peripheral wall 21 a that faces the exterior space. The width of the tunnel 20 defined by the tunnel member 21 (i.e. the horizontal dimension or the dimension of the tunnel 20 in the direction parallel to the longitudinal side of the surface of the pod that is just opposed to the tunnel 20) is designed to be larger than the dimension of the longitudinal side of surface of the pod 2 that is just opposed to the tunnel 20 so that the pod 2 can be received in the tunnel 20. The tunnel 20 opens at the mini environment side opening 20 a and the exterior space side opening 20 b. Thus, the tunnel 20 functions as a tunnel that opens in the vicinity of the space in which the pod 2 is placed (or loaded) on the movable plate 14 to bring the exterior space and the mini environment into communication with each other.

The exterior space side opening 20 b has a width or horizontal dimension equal to the above mentioned width or horizontal dimension of the tunnel 20 and a height or vertical dimension that is designed to be slightly larger than the dimension of the shorter side of the surface of the pod 2 opposed thereto. Thus, the pod 2 can enter the exterior space side opening 20 b. The mini environment side opening 20 a has a width or horizontal dimension that is larger than the horizontal dimension of the tunnel 20 that allows the pod 2 to pass. The width or horizontal dimension of the mini environment side opening 20 a is determined taking into account the size of an L-shaped arm 16 so that an L-shaped arm 16 that will be described later can be disposed aside the pod 2. The height or vertical dimension of the mini environment side opening 20 a is slightly larger than the sum of a dimension that is large enough to provide a housing space 20 c in which the door 15 holding the lid 4 of the pod 2 and a part of the door opening and closing mechanism provided in the tunnel 20 are housed and the above mentioned vertical dimension of the opposed surface of the pod 2.

The length of the tunnel 20 (that is, the distance from the exterior space side opening 20 b to the mini environment side opening 20 a) is determined based on the relationship between the length of two straight portions of the L-shaped arm 16 that supports the door 15 (which will be described later) and the dimension of the shorter side of the lid 4 of the pod 2 or the dimension of the shorter side of the door 15. Specifically, the length of the tunnel 20 is designed in such a way that the portion of the door 15 or the lid 4 that is closest to the mini environment in the state in which door 15 is at a retracted position (i.e. the position that allows transfer of wafers) is kept away from the mini environment and the opening of the pod 2 at the position at which detachment of the lid 4 from the pod 2 is performed (i.e. the lid detachment position) is present in the interior of the tunnel 20. The end wall portion 21 b is designed to limit the exterior space side opening 20 b to the above described size. The horizontal dimension of the end wall portion 21 b is determined according to the relationship between the size of the opposed surface of the pod 2 and the size of the mini environment side opening portion 20 a. The end wall portion 21 b also partly defines the above mentioned housing space 20 c.

The door 15 includes a contact member 15 b and a door body 15 a. The contact member 15 b is a flat plate member having an opposed surface that can be opposed to the lid 4 of the pod 2 and has a shape substantially similar to the lid 4. The door body 15 a holds the contact member 15 b by a flat surface to reinforce the contact member 15 b. The longitudinal dimension of the door body 15 a is shorter than the longitudinal dimension of the mini environment side opening portion 20 a so that the possibility of collision of the door body 15 a with the portion that defines mini environment side opening portion 20 a is prevented from occurring when the door body 15 a is swung upon opening or closing the lid 4. The contact member 15 b is disposed at the center of the door body 15 a with respect to the longitudinal direction thereof. On the surface of the contact member 15 b that is opposed to the pod 2 are provided a suction pads 15 c for holding or retaining the lid 4 by vacuum suction and positioning pins 15 d that determine the positional relationship between the lid 4 and the contact member 15 b. The positioning pins 15 d may have the function of retaining the lid 4. When the positioning pins 15 d have the retaining function, they also serve as so-called latch keys. At positions on the door body 15 a on both sides of the contact member 15 b, there are provided slits 15 e that pass through the door body 15 a from the mini environment side (or the rear side) to the exterior space side (or the front side) and extend parallel to the shorter side of the door body 15 a. Ends (or the fixed ends that will be described later) of the L-shaped arms 16 are attached to portions of the door body 15 a on both sides of the contact member 15 b. The suction pads 15 c and an exhaust system (not shown) that is connected thereto to generate suction force operate as a holding mechanism for objects to be stored or wafers.

The L-shaped arm 16 includes a rotation side straight portion 16 a that is connected at its end with the door opening and closing mechanism 30 by a rotary shaft 30 a that will be described later and a door side straight portion 16 b that is connected at its end with the door body 15 a. The end of the door side straight portion 16 b is the fixed end that is fixed to the door body 15 a. The door side straight portion 16 b extends parallel to the plane of the door body 15 a. The rotary shaft 30 a passes through the tunnel member 21 and connected with the main body of the drive mechanism 30 b of the door opening and closing mechanism 30. The main body of the rotational drive mechanism 30 b is disposed outside the tunnel member 21. The main body of the drive mechanism 30 b includes a known air cylinder and a link mechanism etc. and rotationally drives the rotary shaft 30 a between two predetermined angular positions. The rotary shaft 30 a is oriented perpendicular to the predetermined drive direction of the movable plate 14 and parallel to a plane perpendicular to the pod opening 2 b (i.e. the plane of the wafers stored in the pod).

In the following, the relationship between various dimensions of the space in the tunnel 20 and various dimensions of the L-shaped arm 16 will be described with reference to FIG. 6. In FIG. 6, t1 represents the thickness of the lid 4, w1 represents the dimension of the shorter side of the lid 4, l1 represents the distance from the end face of the fixed end portion of the rotary shaft side straight portion 16 a of the L-shaped arm 16 to the plane of the suction surface of the suction pads 15 c, l1′ represents the distance from the plane of the exterior space side opening 20 b to the plane of the above mentioned suction surface, t2 represents the thickness of the door 15 (including the suction pads, contact member and the door body), L1 represents the sum of the l1 and t2, d1 represents the length of the tunnel 20, 12 represents the length of the door side straight portion 16 b (i.e. distance from the bottom surface of the door 15 to the end face of the portion of the door side straight portion 16 b connected to the rotary shaft side straight portion 16 a that is opposite to the fixed end portion), w2 represents the length of the shorter side of the door 15 (that is, the shorter side length of the contact member or the door body, whichever is the longer in the shorter side dimension), L2 represents the sum of 12 and w2, d2 represents the distance from the inner surface of the lower wall extending in the longitudinal direction and partly constituting the peripheral wall 21 a of the portion of the tunnel 20 into which the door 15 is to be swung and received to the bottom end of the exterior space side opening portion 20 b limited by the end wall portion 21 b, and d3 represents the dimension of the shorter side of the exterior space side opening 20 b. In addition, m1 represents the distance over which the pod 2 is moved backward from the position at which the surface of the lid 4 opposed to the door abuts the suction pads 15 c after the pod 2 has been moved forward to the position at which the pod 2 is stopped after the lid 4 has been detached from the pod 2, and m2 represents the distance over which the pod 2 is moved from the position at which the pod 2 is stopped after the lid 4 has been detached from the pod 2 to the wafer transfer position.

The distance m1 from the position at which the lid 4 of the pod 2 is held to the position at which the lid 4 has been detached is designed to be shorter than the distance l1′ from the surface of the suction pads 15 c to the exterior space side opening portion 20 b of the tunnel, and the thickness t1 of the lid 4 is designed to be shorter than the distance m1. With this feature, the opening and closing operations of the lid 4 are performed always in the interior of the tunnel 20, and entrance of dust or the like into the interior of the pod can be prevented during the opening and closing operations. In addition, by creating air flow from the interior of the tunnel 20 to the exterior space, the amount of dust or the like that enters from the exterior space into the pod through the tunnel before and after the opening and closing operations can be greatly reduced. The travel distance m2 to the wafer transfer position is designed to be shorter than the length of the tunnel 20. Thus, the pod opening is located always in the interior of the tunnel 20 when the wafer transfer is performed. This can prevent the pod opening from being directly exposed to down flow in the mini environment.

The length w2 of the shorter side of the door 15 is designed to be shorter than the dimension d3 of the shorter side of the exterior space side opening portion 20 b of the tunnel 20. By arranging the door at substantially the center of the exterior space side opening portion 20 b with respect to the vertical direction, air flow paths that extend straightly from the mini environment side opening portion 20 a to the exterior space side opening portion 20 b are formed above the upper side of the door 15 and below the lower side of the door 15. These flow paths and the slits 15 e can create air flow toward the exterior space around the door 15. The length w1 of the shorter side of the lid 4 is designed to be equal to or shorter than the length w2 of the shorter side of the door 15 so that the above mentioned air flow paths are formed even when the door 15 is holding the lid 4.

The door 15 that is holding the lid 4 is swung about the rotary shaft 30 a, so that they are received in the housing space 20 c. The above mentioned various dimensions are designed in such a way as to allow this receiving operation. Specifically, the height L2 of the portion including the L-shaped arm 16 and the door 15 before swinging or the sum of dimension 12 and dimension w2 (that is, when the lid is held by the door, the distance between the upper end face of the door or the lid, whichever the higher, and the lowest surface of the L-shaped arm 16) is designed to be shorter than the dimension obtained by subtracting the thickness of the end wall portion 21 b from the length d1 of the tunnel 20. With this design, the door 15 and the lid 4 can be prevented from extending from the interior of the tunnel 20 into the mini environment when they are housed in the housing space in the stationary state.

It is desirable that the sum t1+t2 of the thickness t1 of the lid 4 and the thickness t2 of the door 15 be designed to be smaller than the depth or height d2 of the housing space. It is also desirable that dimension L1 be designed to be smaller than dimension d2. By these designs, the lid 4 and the door 15 do not interfere with the movement of the pod 2 at all when the pod 2 is moved to the position at which the wafer transfer operation is performed. In this embodiment, with a view to make the housing space as small as possible, the L-shaped arms 16 are disposed outside the moving range of the pod 2, and cut portions 21 c are provided on the end wall portion 21 b to prevent it from interfering with the L-shaped arms 16. By these designs, the housing space can be made small, and a space in which air flow may stagnate can be made smaller. Actually, a part of the door 15 or the lid 4 momentarily extends from the interior of the tunnel 20 into the mini environment 25 as the door 15 is swung, but such the time period over which it extends is very short and it does not disturb the down flow significantly. In addition, making the housing space 20 c smaller is more effective in preventing disturbance or generation of dust. Therefore, in this embodiment, the positional relationship of the components only in the stationary state has been considered.

According to the present invention, what is called a mapping sensor is provided for the above described pod and lid opening and closing system for the pod in order to map the wafers stored in the pod. FIGS. 7A, 7B, and 7C show a structure having a mapping sensor in a manners similar to FIGS. 5A, 5B, and 5C. Components the same as those shown in FIGS. 5A, 5B, and 5C are denoted by like reference signs, and they will not be described further. As mentioned before, in this embodiment, a pod that stores two wafers arranged one above the other will be described by way of example. The basic concept of the present invention is that when the pod 2 is kept stationary at a predetermined position, detection light of a transmissive or reflective optical sensor is introduced into the pod through a side wall of the pod to detect the presence/absence of wafers using the detection light. To enable this, the pod 2 to which the present invention is applied has a detection windows 2 c that is made of a material that can transmit the detection light and provided in a side wall of the pod main body 2 a at positions corresponding to a light emitting portion and a light receiving portion (which will be described later) of the sensor according to the position of the sensor in the embodiment that will be described later, as shown in FIG. 7A. The detection window 2 c that allows introduction of detection light from the light emitting portion to the corresponding wafer 1 in the interior of the pod 2 serves as the first detection window, and the detection window 2 c that allows detection light to travel from the interior of the pod 2 to the light receiving portion serves as the second detection window.

In the embodiment shown in FIGS. 7B and 7C, a transmissive sensor is used. As shown in FIGS. 7B and 7C, that apparatus according to this embodiment is provided with a first sensor (or a first mapping sensor) having a first sensor light emitting portion 22 a and a first sensor light receiving portion 22 b for detecting the upper wafer 1 in the pod 2 and a second sensor (or a second mapping sensor) having a second sensor light emitting portion 24 a and a second sensor light receiving portion 24 b for detecting the lower wafer 1. In this embodiment, the sensor light emitting portions 22 a, 24 a and the sensor light receiving portions 22 b, 24 b are fixed on the opposed side walls 21 d, 21 e of the tunnel member 21 that defines the tunnel 20. The sensor light emitting portions 22 a, 24 a and the sensor light receiving portions 22 b, 24 b are arranged in such a way that the axis of the detection light traveling between them obliquely intersects the respective corresponding wafers to be detected. In this embodiment, specifically, either one of the light emitting portion and the light receiving portion of each of the first sensor 22 and the second sensor 24 is disposed at a higher position and the other is disposed at a lower position so that the corresponding wafer 1 is located between them with respect to the thickness or height direction of the pod 2.

More specifically, the first sensor light emitting portion 22 a is disposed above the plane in which the upper wafer 1 extends, and detection light emitted from the first sensor light emitting portion 22 a is emitted obliquely downward toward the plane in which the wafer 1 extends. The corresponding first sensor light receiving portion 22 b is disposed below the plane in which the wafer 1 extends so that it receives the detection light when the wafer 1 is not present and does not receive the detection light when the wafer 1 is present since the detection light is reflected by the wafer 1. The second sensor light emitting portion 24 a and the second sensor light receiving portion 24 b are disposed in such a way that the axis of the sensing light traveling between them is parallel to the axis of the sensing light traveling between the first sensor light emitting portion 22 a and the first sensor light receiving portion 22 b. With respect to the direction along the tunnel 20, the light emitting portions and the light receiving portions are disposed as close to the wall 11 as possible inside the tunnel 20 and within the region over which the wafers 1 in the pod 2 extend at the time when the pod 2 is disposed at the wafer transfer position (i.e. the position shown in FIGS. 5A, 5B, and 5C). The light emitting portions and the light receiving portions of the sensors are fixedly mounted on the side walls 21 d and 21 e respectively in such a way that light emission side end and the light receiving side end (i.e. the ends facing the inner space of the tunnel) of them do not extend into the interior of the tunnel 20. In other words, the light emission side end and the light receiving side end of them are disposed in such a way as to be flush with or recessed from the inner surface of the tunnel member 21 that define the tunnel 20.

The light emitting portion and the light receiving portion used in this embodiment are optical members that function to enhance the directivity of light, and they are separated from a light emitting element that actually emits light and a light receiving element that receives light. The light emitting portion and the light receiving portion are connected respectively with the light emitting element and the light receiving element via optical fibers that are not shown in the drawings. This configuration helps to make the light emitting portion and the light receiving portion more compact and leads to advantages that these portions can be provided on the side walls 21 d, 21 e more easily and attached thereto more simply and that maintenance of cleanness in the interior of the tunnel that will be described later is made more easy. However, the light emitting element and the light receiving element may be directly disposed at the position of the light emitting portion and the light receiving portion in this embodiment, on condition that a significant modification of the tunnel member 21 is not necessitated. This may leads to some loss of the advantages of this embodiment, but provides another advantage of an increase in the stability in the intensity of detection light upon emission and reception. In this embodiment, the detection windows 2 c on the pod 2 are provided separately for the respective corresponding wafers 1. Although this configuration has an advantage that the wall around the detection window 2 c will prevent unexpected light from entering into the light receiving portion, this configuration suffers from disadvantages such as complexity of the structure and an increase in the possibility of entrance of dust or the like into the tunnel with an increase in recesses and protrusions on the surface of the pod. In view of this, the detection windows 2 c may be only two large windows including a first detection window and a second detection window that can be used for all the wafers 1 stored in the pod 2 to make the structure simple.

As described in the foregoing, by providing the sensor light emitting portions and the sensor light receiving portions for wafer mapping, the presence/absence of wafers 1 can be detected upon performing transfer of wafers 1 into/out of the pod 2 before actually taking out the wafers 1 by the robot. As described above, the sensors are arranged in such a way as not to protrude into the tunnel 20 from the opposed side walls 21 d, 21 e of the tunnel member 21 that defines the tunnel 20. Therefore, provisions of these components do not cause additional protrusion into the mini environment 25, which ensures reliability in the movement of the pod 2. In addition, mapping function can be implemented only by sensors etc. in regions adjacent the side walls 21 d, 21 e of the tunnel member in which a space can be provide relatively easily. Therefore, the components related to opening and closing the pod 2 can be arranged one above another along the thickness direction with minimum intervals therebetween, whether the sensors are provided or not. Inside the tunnel 20 is always present clean gas flow coming from the mini environment 25 in which cleanness is controlled toward the exterior space. Therefore, the sensors will not cause contamination of the mini environment 25. In addition, since the sensors are kept in a clean environment, deterioration in its performance and detection errors caused by attachment of dust or the like is prevented.

In the above described embodiment, the axes of light of the sensors are arranged to be parallel to each other in order to prevent interference of light beams for detecting the respective wafers. However, in a case where the upper wafer is absent in this embodiment, there is a possibility that detection light emitted from the second sensor light emitting portion 24 a is reflected by the wafer 1 and a part of the reflected light reaches the first sensor light receiving portion 22 b due to a certain condition of the surface of the wafer 1 to cause a detection error consequently. FIGS. 8 and 9 show arrangements that can perform wafer detection with reduced possibility of detection errors. FIGS. 8 and 9 show the exterior space side opening portion 20 b as seen from the mini environment side opening portion 20 a in a manner similar to FIG. 7C, where only the opening portions and the sensors are illustrated.

In the embodiment shown in FIG. 8, the light emitting portions and the light receiving portions of the first sensor 22 and the second sensor 24 are arranged in such a way that light travels in opposite directions between the first sensor 22 and the second sensor 24. In this arrangement, the arrangements of the optical fibers and the arrangements of the light emitting elements and the light receiving elements may be more complicated as compared to the above described embodiment. However, the possibility of incidence of unintended light reflected by an unexpected region on a desired or predetermined light receiving portion is much lower in this embodiment than the above described embodiment, and it is considered that this embodiment has a significant advantage in preventing detection errors. In the embodiment shown in FIG. 9, the first sensor light emitting portion 22 a is disposed below the level of the upper wafer 1, the first sensor light receiving portion 22 b is disposed above the level of the upper wafer, and the second sensor light emitting portion 24 a and the second sensor light receiving portion 24 b are disposed in the same manner as the embodiment shown in FIG. 7C. Thus, the first sensor light emitting portion 22 a and the second sensor light emitting portion 24 a are arranged relatively close to each other, while the first sensor light receiving portion 22 b and the second sensor light receiving portion 24 b are arranged more distant from each other than in the case of the embodiment shown in FIG. 7C. Although this embodiment may be disadvantageous in providing a space for the first sensor light emitting portion 22 a and the second sensor light emitting portion 24 a that are arranged closed to each other, the large interval between the light receiving portions in this embodiment leads to a lower possibility of incidence of reflected light from an unexpected region on a desired light receiving portion as compared to the embodiment shown in FIGS. 7A, 7B, and 7C. Thus, this embodiment is advantageous in preventing detection errors.

In the above described embodiment, the same type of detection light is used in both the first sensor 22 and the second sensor 24. However, in order to eliminate the possibility of incidence of reflected light from an unexpected region on a desired light receiving portion, it is effective to differentiate the wavelengths of the detection light between the first senor 22 and the second sensor 24. In the case where the wavelength of the detection light used in the first sensor 22 is different from the wavelength of the detection light used in the second sensor, even if detection light emitted from the light emitting portion of the other sensor is received, it will be determined that the predetermined detection light is not actually received, as the received light has a different wavelength. It is also effective to differentiate the emission frequency (or emission cycle) of the detection light between the sensors. In this case, it is possible to determine that light other than detection light received within a predetermined period(s) in the cycle is light reflected from an unexpected region. Thus, it is possible to determine whether true detection light is received or not based on the above-described determination. In this embodiment, the light emitting end of the light emitting portion and the light receiving end of the light receiving portion are arranged to be substantially flush with the inner surface of the tunnel member 21. However, for example, recesses may be provided on the side walls 21 d, 21 e, and the light emitting end and the light receiving end may be arranged at the bottom of the recesses. When this arrangement is adopted, the side walls of the recesses serve as a kind of screens, which effectively reduce the possibility of incidence of reflected light from an unexpected region on a desired receiving portion. Alternatively, wall plates that function as screens may be provided around the light emitting end and the light receiving end to improve directivity of the detection light.

Although transmissive sensors are used in the above described embodiment, reflective sensors may also be used. FIG. 10 shows an embodiment using reflective sensors in a manner similar to FIG. 8. In this embodiment, the portion that is intended to reflect detection light is only the end face of the wafer 1. Therefore, it can be practically challenging to obtain stable reflected light having a sufficient light quantity and appropriate directivity. However, if reflective sensors are used, the number of detection windows 2 c provided on the pod 2 can be reduced. Furthermore, it is possible to arrange the light emitting portion and the light receiving portion side by side. Therefore, reflective sensors can easily be used even in the case where the available space for their implementation is small.

In the following, the actual operation of the lid opening and closing mechanism having the above described structure will be described. The following description will be directed to a case where the first sensor 22 and the second sensor 24 that are shown in FIGS. 7A, 7B, and 7C are used. First, the pod 2 is placed on the movable plate 14 at the loading position, while the opening of the tunnel 20 is substantially closed by the door 15, as shown in FIGS. 1A to 1D. After the pod 2 has been set at a predetermined position on the movable plate 14 with the aid of the positioning pins 14 a, the movable plate 14 is advanced toward the door 15 by a drive mechanism that is not shown in the drawings. The movable plate 14 driven by the drive mechanism is stopped at the position at which the lid 4 that closes the pod 2 comes into abutment with the suction pads 15 c. Upon abutment, the positioning pins 15 d get into positioning recesses (not shown) provided on the lid 4, whereby inappropriate positioning in the abutment of the lid 4 and the door 15 is prevented from occurring. After the abutment, the exhaust mechanism (not shown) is operated, so that the suction pads 15 hold lid 4 by suction. The system in this state is illustrated in FIG. 2A.

After holding of the lid 4 by the door 15 by means of the suction pads 15 c has been achieved, the movable plates 14 on which the pod 2 is set is moved backward to a predetermined lid detachment position. With this backward movement, the lid 4 held by the door 15 is detached from the opening 2 b of the pod 2. At the time of detachment, the lid 4 may possibly be sticking to the pod main body 2 a due to the effect of a sealing member (not shown) or a pressure difference between the interior of the pod 2 and the exterior space. In view of this, it is desirable that the pod main body 2 a be secured to the movable plate 14 by some means. In the case of this embodiment, the positioning pins 14 a are designed to be significantly long so that the pins 14 a retain the pod main body 2 a against the force acting on the pod main body 2 a from the lid 4 during backward movement of the movable plate. FIGS. 3A and 3B illustrate the system in the state in which the movable plate 14 is at the predetermined lid detachment position after it has been moved backward, and the lid 4 has been detached from the pod main body 2 a.

While the movable plate 14 is kept stationary at the above described position, the door 15 is swung by the door opening and closing mechanism 30. The swinging of the door 15 is stopped in the state illustrated in FIGS. 4A and 4B in which the door 15 and the lid 4 are housed in the housing space 20C. Thereafter, the movable plate 14 is moved forward, and at the time when the pod 2 comes to the wafer transfer position (or the position at which the operation of transferring wafers out of/into the pod is to be performed), the movable plate 14 is stopped. The system in this state is illustrated in FIGS. 5 a and 5B. In this state, the first sensor 22 and the second sensor 24 are operated to perform the so-called mapping or the operation of detecting the presence/absence of the upper and lower wafers 1 in the pod 2. The wafer(s) 1 detected by the mapping operation is taken out of the pod 2 and subjected to a predetermined processing. In the aforementioned state, the lid 4 and the door 15 are located beneath the pod 2 with the movable plate 14 between. For this reason and thanks to an additional effect of down flow generated in the mini environment 25, dust or the like on the lid 4 etc. cannot enter the interior of the pod 2 easily. In addition, by generating down flow, the interior of the mini environment is kept at a pressure higher than the pressure in the exterior space. Consequently, flow of gas directed from the mini environment to the exterior space is always present in the tunnel 20, whereby the possibility that dust on the lid 4 or other parts is brought toward the opening 2 b of the pod 2 is further reduced. In the present invention, furthermore, an appropriate gap is designed to be left between the inner surface of the tunnel 20 and the periphery of the door and the outer periphery of the pod in order to achieve the above effect. This gap is designed in such a way that the pressure difference between the mini environment and the exterior space is not made unduly low, and gas flows through that gap at a flow rate that is not unduly high).

In this embodiment, in order to separate the mini environment 25 and the exterior space to a significant extent and to limit the region that allows communication between these spaces, the system is designed in such a way that air flow that flows from inside the housing space 21 straightly to the exterior space cannot be created. However, there is a small gap between the surface of the lid 4 that faces the door 15 and the contact member 15 b in the region other than the region in contact with the suction pads 15 c. If there is dust or the like in that gap, it is considered to be difficult for the above described system to efficiently remove it out to the exterior space. In the case where the degree of dust control in the external environment is not so high, the possibility that dust or the like remains on the opposed surface of the lid 4 would be high. In such an environment, it is preferred that a slit be provided on the end wall portion 21 at a position to be aligned with the above mentioned gap so that an air flow path from the mini environment 25 to the above mentioned gap and then to the slit to facilitate removal of dust in the gap to the exterior space by creating air flow flowing through the gap. In the above described embodiment, the number of wafers 1 stored in the pod 2 is two, and the system adapted to use this pod has been described by way of example. However, the present invention is not limited to this particular embodiment. It is preferred that the number of sensors used for mapping be changed in accordance with the number of wafers 1 stored in the pod 2.

By providing the lid opening and closing system having the above described structure, at the time when the lid of the pod is detached from the pod main body, the lid and the mechanism for opening and closing the lid can be disposed at a position at which they stay out from downward air flow, or specifically, at a position in the tunnel at which any part of them does not extend into the mini environment. In this state, the presence/absence of wafers or the like can be detected, and the operation of transferring wafers or the like out of/into the pod can be performed based on the detection result. Consequently, dust or the like will not be blown off from the lid of the pod or the mechanism for opening and closing the lid by down flow. Other pods, lids, mapping sensors, and drive mechanisms for them etc. are also disposed in the respective tunnels. Therefore, the possibility that dust or the like coming from one lid etc. attaches to another lid or other parts can be reduced. The system enables mapping of wafers or the like stored in the pod without any decrease in the degree of cleanness of the load port having a basic structure by using minimum space.

In the following, a substrate processing apparatus in which the lid opening and closing system described in the foregoing is practically used will be described as an exemplary embodiment of the present invention. FIG. 11 is a side view schematically showing the general structure of a semiconductor wafer processing apparatus (or substrate processing apparatus) 40 that can operate in a so-called mini-environment system. The semiconductor wafer processing apparatus 40 is mainly composed of a load port section (or FIMS system, lid opening and closing apparatus) 10, a transfer chamber (or mini environment) 25, and a processing chamber 29. These sections are separated at their joining portions by the wall 11 on the load port side and the communication passage 28 on the processing chamber side. In the transfer chamber 25 of the semiconductor wafer processing apparatus 40, downward air flow (down flow) from the top to the bottom of the transfer camber 25 is created by a fan filter unit 33 provided in the top portion thereof to keep a high degree of cleanliness by bringing out dust. The bottom panel of the transfer chamber 25 has, for example, a mesh, which provides outlet paths of the down flow. With the above described structure, dust-controlled air is ceaselessly introduced into the transfer chamber 25, and dust present in the chamber or dust brought into the chamber from a pod or other components is always brought downward by the down flow and discharged to the exterior.

Pods 2 or storage containers for silicon wafers or the like (which will be simply referred to as wafers hereinafter) are set on support tables 14 of the load port section 10. In the apparatus according to this embodiment, three pods are set one above another and two wafers 1 are contained in each pod 2. As described before, the interior of the transfer chamber 25 is kept in a highly clean condition for transferring wafers 1. Inside the transfer chamber 25 is provided a transfer robot 35 serving as a wafer transfer mechanism that can actually hold a wafer. The transfer robot 35 can move in the direction along which the pods 2 are arranged (i.e. the vertical direction). The robot arm 35 a of the transfer robot 35 can rotate 360 degrees about an axis. Wafers 1 are transferred between the interior of the pods 2 and the interior of the processing chamber 29 by the transfer robot 35. In the processing chamber 29 are generally provided various systems that perform various processing such as film deposition and film processing on the surface of the wafer. These systems will not be described in further detail herein, since they do to have direct relevance to the present invention.

The pod 2 is composed of a box-like main body 2 a having an opening on one side thereof and an interior space in which two wafers 1 to be processed are to be stored, and a lid 4 that closes the opening. In the interior of the main body 2 a is provided a rack having a plurality of shelves on which wafers are to be placed one above another along one direction. The wafers 1 placed thereon are stored or contained in the interior of the pod 2 at a certain interval. In the exemplary system described herein, the tunnel member 21 has a plurality of tunnels (three tunnels) 20 provided therein at positions corresponding to the movable plates 14. The details of the structure of each tunnel are the same as those of the structure that has been already described above. The structures of the principal components such as the tunnel 20 relevant to the present invention have been discussed in the above description of the embodiment. For this reason and to make understanding of the drawings easier, further description and detailed illustration thereof will not be made.

FIG. 12 is an enlarged view of the lid opening and closing system 10 shown in FIG. 11. In conventional FISM systems adapted to a pod in which a number of wafers are stored, since the lid of the pod necessarily has a somewhat large size, the door that is adapted to detach the lid and closes the opening portion of the mini environment is necessarily required to be moved in the mini environment and stopped in it. In the present invention, since the door has an elongated plate-like shape, the state allowing transfer of wafers out of/into the pod is achieved by enabling relative movement of the pod and the door by an amount equal to the width or thickness of the lid and swinging the door and the lid to outside the moving region of the pod. Accordingly, the door opening and closing mechanism can be disposed in the tunnel that is independent from the mini environment 25 as shown in FIG. 1.

For example, in the case where the robot is driven by a combination of operations of three systems such as X, Y, and Z direction systems, if there are obstacles to be avoided in driving the robot with respect to all the driving directions, a very complex safety circuit is needed in order to achieve safe operation of the robot. In the present invention, there is no structure that extends into the mini environment 25 that can be obstacle to driving of the robot with respect to the vertical direction (or the Z-axis direction). Therefore, a safety circuit is actually needed only when wafers are taken out of or inserted into the pod. Accordingly, the circuit configuration can be made much simpler. Furthermore, since no structure is provided in the mini environment 25 except for the robot 35, there is no structure that can disturb down flow, particularly in the region near the pod opening. Therefore, efficiency of dust removal by the down flow is enhanced. In addition, the possibility of dust generation from the door or other components caused by a disturbance in the down flow is reduced. According to the SEMI (Semiconductor Equipment and Materials International) standards established in the semiconductor industry, it is not allowed to provide a projection on the inner surface of the walls that define the mini environment in the vicinity of the opening portion through which wafers are transferred. The present invention is compliant with the standards.

In the above described embodiment, the movable plate 14 is provided on the support table 13, and the pod 2 is placed thereon. However, the structure to which the present invention is applied is not limited to this embodiment. For example, the pod 2 may be suspended from above. Such a modification is shown in FIG. 13 in a manner similar to FIG. 12. In the case where the pod 2 is transported by so-called automatic handling, an upper flange 2 c fixedly provided on the top surface of the pod 2 is used. The pod 2 is suspended by the flange when transported. In this modification, the pod 2 that has been transported is held by a suspension member 17, and the pod 2 is transferred with the suspension member 17 by a suspension member drive mechanism 19.

In this modification, the movable plate 14 used in the above described embodiment can be eliminated, and the entrance of the plate into the interior of the tunnel 20 with the pod 2 can be prevented. Therefore, it is possible to eliminate the space for receiving the plate that enters, which is required to be provided in the housing space 20 c in the above described embodiment. However, in the above described embodiment, the pod main body 2 a can be retained on the movable plate 14 with a strength that can resist the force acting on the pod main body 2 a upon detachment of the lid 4 to some extent. In this modification, there is a possibility that the simple suspension does not provide a force strong enough to retain the pod main body 2 a upon detachment of the lid, and it may be necessary to design the structure in such a way as to enable retaining of the pod main body or provide an additional component for this purpose. However, since such a component can be additionally used, the storage container support mechanism or the support mechanism in the present invention should be construed to include the structure like that component.

According to the present invention, there can be provided a lid opening and closing system that can perform mapping of wafers stored in a low profile pod upon opening and closing the lid of the pod. This system does not have any component that extends into the mini environment. Since the system does not have component or structure that extends into the pod loading side, full use can be made of the effect of down flow created in the mini environment. In addition, the control program of the transfer robot used in the wafer transferring operation can be made easy and high speed movement of the robot can easily be achieved, since a component or structure to be avoided by the robot upon movement along the Z-axis, in which high speed movement is required, has been eliminated. Furthermore, since the openings of pods are separated by the tunnels, the possibility that dust or the like brought by a certain pod or generated from a certain pod enters another pod can be reduced. Still further, since during the time of wafer transfer, the lid, door, and its drive mechanism are disposed beneath the bottom of the pod and covered by the bottom portion of the pod, the possibility that dust generated from them enters the interior of the pod can be reduced.

Although the above described embodiments or examples have been directed to FOUP and FISM systems, the applications of the present invention are not limited to them. The lid opening and closing apparatus according to the present invention can be applied to any front open type container in which a plurality of objects are to be stored and any system that opens and closes the lid of the container and transfers objects out of/into the container.

As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims. 

1. A lid opening and closing system that detaches a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored in the interior thereof and the lid that can be detached from said main body and close said opening to form a closed space in cooperation with said main body, to open said opening thereby enabling transfer of said object to be stored into/out of said storage container, comprising: a storage container support mechanism that supports said storage container and can move said storage container along a predetermined direction; a mini environment separated from an exterior space, in which a mechanism that transfers said object to be stored is housed under dust control; a tunnel having an exterior space side opening portion disposed near a position at which said storage container support mechanism is loaded with said storage container and a mini environment side opening portion that opens to said mini environment to establish communication with said mini environment; a door that can open and close said mini environment side opening, said door having a holding mechanism that is in contact with and holds said lid and being movable, in a posture in which it is oriented perpendicular to the direction in which said tunnel extends to substantially close said tunnel, along said predetermined direction relative to said storage container that is moved by said storage container support mechanism disposed in said tunnel; and a mapping sensor provided within said tunnel, that includes a light emitting portion that emits detection light to an object to be stored held in said storage container and a light receiving portion that receives said detection light to detect the presence/absence of said object to be stored.
 2. A lid opening and closing system according to claim 1, wherein said light emitting portion and light receiving portion are disposed in accordance with the position of said object to be stored in the interior of said storage container in a state in which said storage container is located at a position at which transfer of said object to be stored into/out of said storage container is performed.
 3. A lid opening and closing system according to claim 1, wherein there are a plurality of objects to be stored like said object to be stored, there are a plurality of mapping sensors like said mapping sensor provided for said objects to be stored respectively, and at least one of a wavelength range and an emission frequency of said detection light used by said mapping sensors differs among said mapping sensors.
 4. A lid opening and closing system according to claim 1, wherein there are a plurality of objects to be stored like said object to be stored, there are a plurality of mapping sensors like said mapping sensor provided for said objects to be stored respectively, and the light emitting portion of one of said mapping sensors and the light receiving portion of the mapping sensor disposed just above or below said one mapping sensor are disposed on an inner surface of said tunnel and at a position opposed to one side of said storage container.
 5. A lid opening and closing system according to claim 1, wherein there are a plurality of objects to be stored like said object to be stored, there are a plurality of mapping sensors like said mapping sensor provided for said objects to be stored respectively, the light emitting portion of a first mapping sensor among said plurality of mapping sensors and the light emitting portion of a second mapping sensor among said plurality of mapping sensors that is disposed just above or below said first mapping sensor are disposed on an inner surface of said tunnel and at positions opposed to one side of said storage container, and the distance between an axis of detection light emitted from the light emitting portion of said first mapping sensor and an axis of detection light emitted from the light emitting portion of said second mapping sensor increases away from said light emitting portions.
 6. A lid opening and closing system according to claim 1, wherein a light emission side end of said light emitting portion and a light receiving side end of said light receiving portion are disposed in such a way as to be flush with or recessed from the inner surface of said tunnel.
 7. A lid opening and closing system that detaches a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored in the interior thereof and the lid that can be detached from said main body and close said opening to form a closed space in cooperation with said main body, to open said opening thereby enabling transfer of said object to be stored into/out of said storage container, comprising: a storage container support mechanism that supports said storage container and can move said storage container along a predetermined direction; a mini environment separated from an exterior space, in which a mechanism that transfers said object to be stored is housed under dust control; a tunnel having an exterior space side opening portion disposed near a position at which said storage container support mechanism is loaded with said storage container and a mini environment side opening portion that opens to said mini environment to establish communication with said mini environment; and a door that has a holding mechanism that is in contact with and holds said lid, is disposed inside said tunnel, can swing about a rotational axis perpendicular to said predetermined direction and parallel to a plane in which said object to be stored extends, and is movable, in a posture in which it is oriented perpendicular to the direction in which said tunnel extends to substantially close said tunnel, along said predetermined direction relative to said storage container that is moved by said storage container support mechanism disposed in said tunnel, wherein said tunnel allows the opening of said storage container to be located in said tunnel when said door has moved relative to said storage container to detach said lid from said storage container and has a size large enough to have a housing space that can house said door and said lid without interfering with movement of said storage container in said predetermined direction when said door with said lid held by it has been swung about said rotational axis, and a mapping sensor that includes a light emitting portion that emits detection light to an object to be stored held in said storage container and a light receiving portion that receives said detection light, to detect the presence/absence of said object to be stored, is provided within said tunnel.
 8. A lid opening and closing system according to claim 7, wherein said light emitting portion and light receiving portion are disposed in accordance with the position of the object to be stored in the interior of said storage container in a state in which said storage container is located at a position at which transfer of said object to be stored into/out of said storage container is performed.
 9. A lid opening and closing system according to claim 7, wherein there are a plurality of objects to be stored like said object to be stored, there are a plurality of mapping sensors like said mapping sensor provided for said objects to be stored respectively, and at least one of a wavelength range and an emission frequency of said detection light used by said mapping sensors differs among said mapping sensors.
 10. A lid opening and closing system according to claim 7, wherein a light emission side end of said light emitting portion and a light receiving side end of said light receiving portion are disposed in such a way as to be flush with or recessed from the inner surface of said tunnel.
 11. An object to be stored transfer system that transfers an object to be stored into/out of a storage container using a lid opening and closing system, comprising the lid opening and closing system according to claim 1 and said storage container, wherein said storage container is provided with a first detection window that can transmit said detection light and allows said detection light emitted from said light emitting portion to reach the corresponding object to be stored and a second detection window that can transmit said detection light and allows said detection light to reach said light receiving portion from the interior of said storage container.
 12. An object to be stored transfer system according to claim 11, wherein there are a plurality of objects to be stored like said object to be stored, and said first detection window and said second detection window are provided separately for the respective corresponding objects to be stored.
 13. An object to be stored processing method for detaching a lid of a storage container having a substantially box-like main body having an opening on one side thereof that can store an object to be stored in the interior thereof and the lid that can be detached from said main body and close said opening to form a closed space in cooperation with said main body to open said opening thereby enabling transfer of said object to be stored into/out of said storage container, transferring said object to be stored into/out of said storage container, and performing a predetermined processing on said object to be stored in the exterior of said storage container, comprising the steps of: preparing a lid opening and closing system including a dust-controlled mini environment, a transfer mechanism that transfers an object to be stored and is provided in said mini environment, a door that can substantially close an opening portion of said mini environment and hold said lid, and a support mechanism that supports said storage container and moves said storage container in a predetermined direction to cause said door to hold said lid; causing said storage container to be supported on said support mechanism and fixing said storage container on said support mechanism; driving said support mechanism to cause said lid to abut to said door thereby causing said door to hold said lid; driving said support mechanism and said door in said predetermined direction relative to each other to thereby separate said storage container and said lid; swinging said lid and door about an axis that is perpendicular to said predetermined direction and contained in a plane in which said object to be stored extends to thereby bring said lid and door out of a moving region of said storage container; and driving said storage container in said predetermined direction to set it at a position at which transfer of said object to be stored into/out of said storage container is performed, wherein said storage container is located inside a tunnel that connects said mini environment and a space in which operation of causing said storage container to be supported on said support mechanism is performed at the time when said lid is separated from said storage container, said lid and door are located inside said tunnel after said swinging, and said storage container is located inside said tunnel when it is located at the position at which transfer of said object to be stored into/out of it is performed, when said storage container is located at the position at which transfer of said object to be stored is performed, detection light is cast to said object to be stored through a first detection window that can transmit the detection light provided on said storage container, and whether said object to be stored is present or absent is determined based on whether or not the detection light reflected by said object to be stored is received through a second detection window that can transmit the detection light. 